Unequal key ratios: puzzler

David Love davidlovepianos@earthlink.net
Fri, 15 Feb 2002 07:31:12 -0800


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Recently rebuilt a S&S model S c 1931.  The measured key ratios for the =
sharps were .48, for the naturals .51.  I considered moving the capstans =
on the sharps so the total leverage on each would be equal.  But when I =
started to set up samples and take measurements, I found that the FW =
pattern was smooth and the corresponding SWR's were equal.  I would have =
expected that sharps to need less FW or, with a smooth line front =
weighting,  a varied SWR.  Somewhere in the system something else =
compensated for the different key ratios.  Question is where?  All new =
parts, strike weights smoothed, BW all equal.  the job is now completed. =
 I left the capstan positions alone and the FW curve was pretty smooth, =
SWR all 5.9 - 6.0.  A few bumps along the road as is often the case, but =
one would have expected 6-10 grams less FW on the sharps.  Any opinions?

David Love
=20

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